Metal oxide particles (nano-, submicro- and microparticles) are used in many areas including polymer and particle composites, Pickering emulsions, photocatalysis and even in sunscreens. However, the use of these particles in lipophilic materials such as polymers or in sunscreen lotions necessitates their surface treatment to yield hydrophobic particles. This allows stable dispersions and composites of these particles to be formed. As such, a simple and economical process for hydrophobicization of such metal oxide particles is extremely important.
Further, the use of physical sunscreens such as zinc oxide (ZnO) and titanium dioxide (TiO2) necessitates the encapsulation of ZnO or TiO2 particles with silicon dioxide (SiO2) or alumina to minimize the formation of reactive oxygen species (ROS) on the particulate surfaces due to charge separation when the particles are exposed to UV irradiation. As such, the utilization of such sunscreens in the presence of free radical scavengers such as ascorbic acid would be beneficial in aiding the quenching of these ROS. Further, it would be beneficial if the scavengers are released upon UV irradiation, to wipe up free radical species as they are formed.
It is well known to persons skilled in the art that dry water essentially refers to micronized droplets of water encapsulated by hydrophobic particles. Dry water is of wide interest to the industrial community, in particular, for the use of cosmetic compositions and also as dry paints.
On a similar note, the term “dry oil” as used herein refers to micronized liquid marbles of oil-based liquids.
Controlled release of an active substance, whereby the release is typically triggered or activated upon application of or exposure to a stimulus, is desirable in many applications. For example, in the agricultural context, the stimuli-responsive release of biocides, pesticides, fungicides, herbicides, or fertilizers is extremely useful.
In other contexts, the stimuli-induced release can also be useful for self-healing materials, release of inks, or fragrances.